TOUCH-SENSITIVE SURFACE

• US 20120218218A1
• Filed: 02/28/2011
• Published: 08/30/2012
• Est. Priority Date: 02/28/2011
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Kauko, Jarmo
• Granted Patent: US 9,223,446 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/04186 Touch location disambiguation
• CPC Class Codes: G06F 3/044 by capacitive means

Abstract

A body part of a user touching a touch sensitive surface is determined based on a measured electrostatic signal. The electrostatic signal is transmitted by a transmitter and received by a receiver using a capacitively coupled human body as a communication channel. A touch signal is provided by the touch sensitive surface being touched by the user. The received electrostatic signal is measured in response to the touch signal and the body part of the user touching the touch sensitive surface is determined.

Claims

1. An apparatus comprising:

a transmitter configured to send an electrostatic signal;

a receiver configured to receive the electrostatic signal using a capacitively coupled human body as a communication channel;

a touch sensitive surface configured to provide a touch signal;

wherein

the apparatus is configured at least to;

measure the received electrostatic signal in response to the touch signal; and

determine a body part of a user touching the touch sensitive surface based on the measured electrostatic signal.

2. The apparatus of claim 1, wherein the apparatus is further configured to:

define a circuit length for the received electrostatic signal; and

determine the body part of the user touching the touch sensitive surface based on the circuit length for the received electrostatic signal.

3. The apparatus of claim 2, wherein the apparatus is further configured to:

define circuit impedance based on the received electrostatic signal; and

define the circuit length for the received electrostatic signal using the circuit impedance.

4. The apparatus of claim 3, wherein the circuit impedance depends on at least capacitance and resistance of the communication channel between the transmitter and the receiver.

5. The apparatus of claim 4, wherein the capacitance of the communication channel comprises at least first capacitance between the transmitter of the apparatus and a first body part of the user, and second capacitance between a second body part of the user and the touch sensitive surface.

6. The apparatus of claim 2, wherein the circuit length for the received electrostatic signal is defined using at least one of the following:

a strength of the received electrostatic signal and a timing of the received electrostatic signal.

7. The apparatus of claim 1, further comprising:

a ground configured to provide a return path for the electrostatic signal, wherein the ground is at least one of the following;

an air ground and an earth ground.

8. The apparatus of claim 1, wherein the transmitter comprises a conductive sheet located in an insulating cover part of the apparatus.

9. The apparatus of claim 8, wherein the conductive sheet is in the cover part next to the user'"'"'s first palm when the user is operating the apparatus.

10. The apparatus of claim 1, wherein the apparatus is further configured to:

determine the body part of the user between a first hand and a second hand.

11. The apparatus of claim 10, wherein the apparatus is further configured to:

in response to the determining of the first hand, initiate a first function; and

in response to the determining of the second hand, initiate a second function.

12. The apparatus of claim 10, wherein the first function comprises at least one of the following:

selecting an item on the touch sensitive surface, activating a function, and opening a first context menu for the user.

13. The apparatus of claim 10, wherein the second function comprises at least opening a second context menu for the user.

14. The apparatus of claim 13, wherein the second context menu is configured to be displayed as a round-shaped rendered object on the touch sensitive surface next to a touch position of the user touching the touch sensitive surface.

15. The apparatus of claim 1, further comprising:

an actuator configured to provide a signal path for the electrostatic signal between the body part of the user touching the touch-sensitive surface and the touch sensitive surface.

16. The apparatus of claim 1, further comprising:

at least one processor; and

at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus at least to;

measure the received electrostatic signal in response to the touch signal; and

determine a body part of a user touching the touch sensitive surface based on the measured electrostatic signal.

17. A method comprising:

transmitting an electrostatic signal;

receiving the electrostatic signal using a capacitively coupled human body as a communication channel;

providing a touch signal by a touch sensitive surface being touched by a user;

measuring the received electrostatic signal in response to the touch signal; and

determining a body part of the user touching the touch sensitive surface based on the measured electrostatic signal.

18. The method of claim 17, further comprising:

defining a circuit length for the received electrostatic signal; and

determining the body part of the user touching the touch sensitive surface based on the defined circuit length for the received electrostatic signal.

19. The method of claim 18, further comprising:

defining circuit impedance based on the received electrostatic signal; and

defining the circuit length for the received electrostatic signal using the circuit impedance.

20. A computer program embodied on a computer readable medium comprising computer executable program code which, when executed by at least one processor of an apparatus, causes the apparatus to:

transmit an electrostatic signal;

receive the electrostatic signal using a capacitively coupled human body as a communication channel;

provide a touch signal by a touch sensitive surface being touched by a user;

measure the received electrostatic signal in response to the touch signal; and

determine a body part of the user touching the touch sensitive surface based on the measured electrostatic signal.